For pet owners, it can be hard to tell if they’ve really got a sick puppy (or kitty) on their hands, or if they’re just being crazy. Photo: Alamy

I’m always worried about Lester,” says Louise Rozett, 41, a writer of young-adult fiction who lives in Brooklyn. “I love him as much if not more than anyone or anything in my life, so when I think there might be a problem, it’s pretty much all I can think about.”

Rozett isn’t talking about her child or a romantic partner, but rather her 2-year-old Bernese mountain dog. “I really have to force myself not to pick up the phone and call the vet for every little thing,” she says.

As with many who have animals in the city, her pup’s health and well-being is an ever-present worry that walks the fine line between legitimate concern and pet-focused hypochondria.

“People in New York are very in tune with their animals and very proactive,” says Dr. Kristin Lester, a veterinarian with the Seaport Animal Hospital in lower Manhattan. “Sometimes you notice something very subtle and it turns out to be really significant. But…it could be nothing, just a change in barometric pressure.”

Dr. Hilary Nims, a veterinarian at Hope Veterinary Services in Boerum Hill, Brooklyn, says she’s become accustomed to managing neurotic pet owners and has observed that pet-hypochondria tends to afflict young couples who get a pet to test their caretaking abilities before having a child.

Recently, she recalls, a couple brought their terrier into the practice. The woman had become concerned about a small bump on its head, and also feared the dog might be sick because he’d eaten a sweet potato. It was evident the boyfriend found it all a bit absurd. “Those are the most difficult, when one [owner] has taken on the maternal role and one is more dismissive,” she says. In the end, the dog ended up having a developmental eye disease, and the boyfriend was humbled. “It’s better to be safe than sorry,” Nims cautions.

How can pet owners deduce when their concern is legitimate and when they’re being overly neurotic? Here, some tips:

* Don’t miss your checkups: The ASPCA recommends that cats and dogs get an annual physical. Senior pets should be checked out twice a year.

* Know what’s normal: Juliet Sternberg, the director of Hope Veterinary Services, has heard from cat owners concerned that their pet is sleeping all day, but that’s actually prototypical feline behavior. Lester suggests that owners should read up on the health-related quirks common to their animals’ breed and age.

* Consider waiting it out: While it can be scary to see your pet projectile vomiting, a onetime incident doesn’t necessarily mean you need to rush to the vet. “If the dog is still standing, and they’re wagging their tail, one episode is fine,” Nims says, “especially if he’s still eating.”

* But leave the doctoring to the doctor: Drugs that appear virtually harmless to humans, such as ibuprofen, can kill a dog, says Nims. A professional should make all medication decisions. Also, be wary of relying on the Internet for medical advice. There’s a fine line between learning more about your kitty and diagnosing him.